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Non-Communicable Diseases Watch November 2018

Chronic Obstructive Pulmonary Disease : An Overview

This publication is produced by the Surveillance and Epidemiology Branch, Centre for Health Protection of the Department of Health

18/F Wu Chung House, 213 Queen’s Road East, Wan Chai, Hong Kong http://www.chp.gov.hk All rights reserved

Key Messages

Chronic obstructive pulmonary disease (COPD) is a life-threatening progressive lung disease

characterised by a persistent reduction of airflow resulting from chronic inflammation in the lung

and remodeling of small airways.

Major but modifiable risk factors of COPD are tobacco smoking, outdoor and indoor air pollution,

as well as occupational exposures to air-borne pollutants.

In Hong Kong, the Population Health Survey 2014/15 reported that 0.5% (0.6% in males; 0.4%

in females) of non-institutionalised persons aged 15 and above had doctor-diagnosed COPD.

The disease accounted for over 30 000 episodes of inpatient discharges and deaths in 2016 and 1 223

registered deaths in 2017.

In May 2018, the Hong Kong SAR Government launched “Towards 2025: Strategy and Action Plan

to Prevent and Control Non-communicable Diseases in Hong Kong” with a list of committed actions,

pursuing to achieve the target to reduce premature mortality from non-communicable diseases,

including COPD and other chronic respiratory diseases (CRDs) by 2025.

For prevention, early detection and management of COPD and other CRDs, the Government will

adopt a stronger and multi-pronged approach in tobacco control; identify and initiate practicable air

pollution control and air quality improvement measures; strengthen the health system at all levels for

prevention, early detection and management of COPD and other CRDs; review and update drug lists

and clinical protocols regularly to ensure effective treatment of COPD and other CRDs; and organise

large scale and systematic health communication campaigns to encourage the public to make changes

for better health (such as quit smoking).

Individuals too can contribute to the fight against COPD by avoiding tobacco and adopting healthy

lifestyle practices.

Target 1: Reduce premature mortality from non-communicable diseases,

including COPD and other CRDs

Chronic Obstructive Pulmonary Disease : An Overview

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Non-Communicable Diseases Watch November 2018

Chronic respiratory diseases (CRDs) refer to a

spectrum of diseases of the airways and other

structures of the lungs. They are among the leading

causes of morbidity and mortality worldwide. Some

of the most common CRDs are chronic obstructive

pulmonary disease (COPD), asthma, respiratory

allergies, occupational lung diseases, lung cancer

and pulmonary hypertension. COPD is a life-

threatening progressive lung disease characterised

by a persistent reduction of airflow resulting from

chronic inflammation in the lung and remodeling

of small airways.1, 2 The Global Burden of Disease

Study estimated that 3.2 million people died from

COPD in 2015, with an increase of 11.6% com-

pared with 1990. The number of prevalent COPD

cases also increased by 44.2% during the same

period, to 174.5 million in 2015.3 Of note, COPD

tends to be under-diagnosed, especially in younger

patients, never or current smokers, patients with less

severe airflow limitation or lower education.4

Risk Factors of COPD

One of the hallmarks of COPD is an accelerated

decline in lung function. In general, lung function

increases with age during childhood and adoles-

cence, and reaches the maximum at approximately

20 years of age. Lung function then plateaus and

starts to decline gradually from around 35 years of

age as a feature of normal ageing.5, 6 However, a

number of risk factors (Box 1) across the lifespan

can impair normal lung growth and development,

limit the maximal lung function attained, shorten the

duration of the plateau phase prior to the decline

with normal ageing, or accelerate the decline in lung

function and lead to COPD.2, 6, 7 Although some of

the COPD risk factors (such as advancing age or

gene defect) cannot be changed, smoking and other

environmental factors are modifiable.

Tobacco Smoking

While the human lung is subjected to air pollutants

and irritants with each breath, tobacco smoking is

the most commonly encountered risk factor of

COPD. Globally, between 40–73% of COPD

mortality is related to smoking tobacco.7 Compared

with never smokers, current and ever smokers were

about 3.5 times and 2.9 times as likely to develop

COPD respectively.8 However, tobacco smoking

affects not only smokers. It has been shown that 25–

45% of patients with COPD have never smoked.9

There is also sufficient evidence supporting an

association between secondhand smoke exposure

and COPD development and acute exacerbation.6, 10

In utero exposure to maternal smoking can negative-

ly affect foetal lung growth, leading to lung function

impairment in childhood and subsequently predis-

posing to COPD development in adulthood.11

Box 1: Major Risk Factors for COPD

Environmental Exposures

● Passive smoking ● Indoor air pollution (e.g. from burning

wood, animal dung and other biofuels for

cooking or heating) ● Outdoor air pollution (e.g. from fossil fuel

combustion in motor vehicle emissions) ● Occupational exposure to air-borne pollu-

tants (including dusts, chemicals, gases and

fumes)

Host Factors

● Smoking ● Advancing age ● Gene defect (e.g. deficiency of the enzyme

α 1-antitrypsin that protects the lung from

damage)

● Respiratory infection (such as pulmonary

tuberculosis*)

● Co-morbidities (such as chronic asthma*) ● Early life insults (such as in utero exposure to

maternal smoking)

Note: * Tuberculosis and chronic asthma are associated with irreversible loss of lung function, but it is uncertain whether the

related clinical features are phenotypically different from those of COPD.

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Non-Communicable Diseases Watch November 2018

Compared to people who had not been exposed to

secondhand smoke during childhood, those who had

been exposed to secondhand smoke would have

50–90% increased risk of COPD later in life.12 Like

tobacco, e-cigarettes contain toxic chemicals that

affect the smoker’s lung. Among adults, studies

found that use of e-cigarettes could increase the risk

of developing chronic respiratory diseases including

COPD.13

Air Pollution

Apart from tobacco smoking, air pollution (indoor

and outdoor) can also produce deleterious effects on

the small airways and cause an accelerated decline in

lung function. There is ample evidence supporting the

association between high concentrations of outdoor

air pollutants (especially ozone, sulfur dioxide and

particulate matters) with COPD exacerbation.6, 14

Of 4.2 million outdoor air pollution-related premature

deaths worldwide in 2016, COPD accounted for

18%.15 In low- and middle-income countries, one in

four (25%) premature deaths from COPD among

adults are due to exposure to indoor air pollution.

Compared with women who use cleaner fuels and

technologies, women exposed to high levels of in-

door smoke are more likely to suffer from COPD by

over 2 times. Among men, exposure to household air

pollution would also nearly double that risk.16

Occupational Exposure

Occupational exposure to air-borne pollutants

(including dusts, chemicals, gases and fumes) as an

important cause of COPD has been recognised for

years. The population-attributable fraction for

occupational exposure to COPD risk is estimated to

be 15–20%.6 A study of 3 343 participants who were

randomly selected in 12 countries with 20 years of

follow-up showed that those exposed to biological

dust, pesticides, gases and fumes at work had 60%,

120% and 50% higher risk of COPD respectively

compared with those unexposed.17

Burden of COPD in Hong Kong

With the prevalence of daily cigarette smoking

hitting 30-year low at 10.0% among people aged

15 and over in 2017,18 the Population Health Survey

conducted by the Department of Health (DH) be-

tween December 2014 and October 2015 observed

that 0.5% (0.6% in males; 0.4% in females) of

non-institutionalised persons aged 15 and above

had doctor-diagnosed COPD,19 showing a marked

decrease in the prevalence from 1.4% (1.9% in

males; 0.9% in females) in 2003/04.20 Nevertheless,

COPD exacerbations often require hospital admis-

sion. In 2016, there were over 30 000 episodes of

inpatient discharges and deaths attributed to COPD

in public and private hospitals.21 Furthermore, the

disease accounted for 1 223 registered deaths in 2017,

representing 2.7% of all registered death in that

year.22 As shown in Table 1, morbidity and mortality

attributed to COPD increased exponentially with age.

Age group Prevalence of doctor-diagnosed COPD,

2014/15

Episodes of inpatientdischarges and deaths,

2016

Registered deaths, 2017

Number Rate* Number Rate^ Number Rate^

44 and below

6 800 0.2 1 297 33.7 2 0.1

45–64 10 100 0.5 3 720 159.8 72 3.1

65 and above

13 000 1.2 25 783 2 216.6 1 149 94.6

Total 29 900 0.5 30 800 419.8 1 223 16.5

Table 1: Disease Burden of COPD

Notes: * Rate per 100 mid-year population of respective age group; ^ Rate per 100 000 mid-year population of respective age group.

Sources: Department of Health, Census and Statistics Department, Hospital Authority.

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Non-Communicable Diseases Watch November 2018

Reduce Premature Mortality from COPD and other CRDs

The Government of the Hong Kong Special

Administrative Region is committed to protect

population health and reduce the disease burden

from non-communicable diseases (NCD), including

COPD and other CRDs. On 4 May 2018, the Govern-

ment launched “Towards 2025: Strategy and Action

Plan to Prevent and Control Non-communicable

Diseases in Hong Kong” (SAP) with 9 local NCD

targets to be achieved by 2025 (Box 2). The main

focus of SAP is on the four major NCD (i.e. CRDs,

along with diabetes, cardiovascular diseases and

cancer) and four potentially modifiable behavioural

risk factors (namely tobacco use, harmful use of

alcohol, unhealthy diet and physical inactivity).

It has put forward a systematic portfolio of policies,

programmes and actions that Hong Kong will

pursue to achieve a 25% relative reduction in risk

of premature mortality (i.e. dying between ages 30

and 70) from the four NCD (including COPD and

other CRDs) by 2025.23

For prevention and treatment of COPD and other

CRDs, the Government will adopt a stronger

multi-pronged approach in tobacco control (including

e-cigarettes); identify and initiate practicable air

pollution control and air quality improvement

measures (such as measures to reduce emissions

from vehicles, vessels, industrial sources and power

plants; pursuit of renewable

energy in increasing the use

of wind and solar energy in

electricity generation); strength-

en the health system at all levels,

in particular a comprehensive

primary care for prevention,

early detection and management

of COPD and other CRDs based

on the family doctor model;

review and update drug lists

and clinical protocols regularly

based on scientific and clinical

evidence to ensure equitable

access by patients to cost-

effective drugs and therapies

of proven safety and efficacy

for treatment of COPD and

other CRDs in all public hospi-

tals and clinics; and organise

large scale and systematic

health communication cam-

paigns to encourage the public

to make changes for better

health (such as quit smoking).23

Box 2: 9 local NCD targets by 2025

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Non-Communicable Diseases Watch November 2018

Individuals too can contribute to the fight against

COPD by keeping the lungs healthy. Key actions

include:

Do not smoke, and avoid secondhand smoke.

Smokers are encouraged to call DH’s Integrated

Smoking Cessation Hotline 1833 183 for

further information. There are a number of

smoking cessation clinics run by DH and

Hospital Authority. DH also subvents some

non-governmental organisations, such as Tung

Wah Group of Hospitals and Pok Oi Hospital

to provide free smoking cessation services in

the community. For details, please visit the

website of the Tobacco and Alcohol Control

Office at http://www.taco.gov.hk;

Be aware of air pollution. Monitor public

announcements of ambient air quality. Stay

indoors when outdoor air quality is poor;

Observe occupational safety and health rules

to minimise occupational exposures and protect

the lungs from hazard at work;

Exercise regularly to keep the lungs healthy

and maintain overall fitness;

Get appropriate vaccinations against influenza

and pneumococcal disease as recommended by

the doctor.

For more information about the Government key

initiatives and specific actions to reduce premature

mortality from COPD and other CRDs, please

refer to the SAP which can be found at the

Change for Health Website of DH

https://

www.change4health.gov.hk/en/saptowards2025/.

References

1. Chronic Obstructive Pulmonary Disease (COPD). Geneva: World

Health Organization, 16 November 2016.

2. Rabe KF, Watz H. Chronic obstructive pulmonary disease. Lancet

2017; 389(10082):1931-1940.

3. Global, regional, and national deaths, prevalence, disability-

adjusted life years, and years lived with disability for chronic

obstructive pulmonary disease and asthma, 1990-2015: a systemat-

ic analysis for the Global Burden of Disease Study 2015. Lancet

Respir Med 2017; 5(9):691-706.

4. Bernd L, Joan BS, Michael S, et al. Determinants of underdiagno-

sis of COPD in national and international surveys. Chest 2015; 148

(4):971-985.

5. Lung Capacity and Aging. American Lung Association. Available

at http://www.lung.org/lung-health-and-diseases/how-lungs-work/

lung-capacity-and-aging.html (accessed on 30 May 2018).

6. Eisner MD, Anthonisen N, Coultas D, et al. An official American

Thoracic Society public policy statement: Novel risk factors and

the global burden of chronic obstructive pulmonary disease.

Am J Respir Crit Care Med 2010; 182(5):693-718.

7. Mannino DM, Buist AS. Global burden of COPD: risk factors,

prevalence, and future trends. Lancet 2007; 370(9589):765-73.

8. Forey BA, Thornton AJ, Lee PN. Systematic review with

meta-analysis of the epidemiological evidence relating smoking

to COPD, chronic bronchitis and emphysema. BMC Pulm Med

2011; 11:36.

9. Salvi SS, Barnes PJ. Chronic obstructive pulmonary disease in

non-smokers. Lancet 2009; 374(9691):733-43.

10. Fischer F, Kraemer A. Meta-analysis of the association between

second-hand smoke exposure and ischaemic heart diseases, COPD

and stroke. BMC Public Health 2015; 15:1202.

11. Savran O, Ulrik CS. Early life insults as determinants of chronic

obstructive pulmonary disease in adult life. Int J Chron Obstruct

Pulmon Dis 2018; 13:683-693.

12. Johannessen A, Bakke PS, Hardie JA, Eagan TM. Association of

exposure to environmental tobacco smoke in childhood with

chronic obstructive pulmonary disease and respiratory symptoms

in adults. Respirology 2012; 17(3):499-505.

13. Perez MF, Atuegwu N, Mead E, et a. E-cigarette use is associated

with emphysema, chronic bronchtis and COPD. Am J Respir Crit

Care Med 2018; 197:A6245.

14. Li J, Sun S, Tang R, et al. Major air pollutants and risk of COPD

exacerbations: a systematic review and meta-analysis. Int J Chron

Obstruct Pulmon Dis 2016; 11:3079-3091.

15. Ambient (Outdoor) Air Quality and Health. Geneva: World Health

Organization, May 2018.

16. Household Air Pollution and Health. Geneva: World Health

Organization, 8 May 2018.

17. Lytras T, Kogevinas M, Kromhout H, et al. Occupational expo-

sures and 20-year incidence of COPD: the European Community

Respiratory Health Survey. Thorax 2018.

18. Thematic Household Survey Report No. 64. Pattern of Smoking.

Hong Kong SAR: Census and Statistics Department, March 2018.

19. Population Health Survey 2014/15. Hong Kong SAR: Department

of Health.

20. Population Health Survey 2003/04. Hong Kong SAR: Department

of Health.

21. Inpatient Statistics 2016. Hong Kong SAR: Hospital Authority,

Department of Health and Census and Statistics Department.

22. Mortality Statistics 2017 (Provisional). Hong Kong SAR:

Department of Health and Census and Statistics Department.

23. Towards 2025: Strategy and Action Plan to Prevent and Control

Non-communicable Diseases in Hong Kong. Hong Kong SAR:

Food and Health Bureau, May 2018.

Page 6

World COPD Day

21 November 2018

World COPD Day is an annual event. Organised by the Global Initiative for Chronic Obstructive

Lung Disease (GOLD) in collaboration with health care professionals and COPD patient groups

throughout the world, it aims to raise public awareness about COPD and improve COPD care.

The first World COPD Day was held in 2002. Each year GOLD chooses a theme and organisers

in more than 50 countries worldwide carrying out various activities, making the day one of the

world’s most important COPD awareness and education events. For 2018, the World COPD Day

will take place on 21 November around the theme “Never Too Early, Never Too Late”.

To learn more about the World COPD Day and related information, please visit http://goldcopd.org/

world-copd-day/.

Non-Communicable Diseases Watch November 2018

Non-Communicable Diseases (NCD) WATCH is dedicated to

promote public’s awareness of and disseminate health information

about non-communicable diseases and related issues, and the

importance of their prevention and control. It is also an indication of

our commitments in responsive risk communication and to address

the growing non-communicable disease threats to the health of our

community. The Editorial Board welcomes your views and comments.

Please send all comments and/or questions to so_dp3@dh.gov.hk.

Editor-in-Chief

Dr Regina CHING

Members

Dr Thomas CHUNG Dr Ruby LEE

Dr Cecilia FAN Mr YH LEE

Dr Anne FUNG Dr Eddy NG

Dr Rita HO Dr Lilian WAN

Dr Karen LEE Dr Karine WONG